Continuous dilution apparatus



Dec. 3, 1968 E. w. CATANZARO CONTINUOUS DILUTION APPAR ATUS Filed Aug. 18, 1966 5904 0/4 uavr INVENTOR. 660 6 M Chm/Yaw BY I G 9 75 Marc United States Patent 3,414,238 CONTINUOUS DILUTION APPARATUS Eugene W. Catauzaro, Paramus, N.J., assignor to Technicon Corporation, a corporation of New York Filed Aug. 18,1966, Ser. No. 573,258 5 Claims. (Cl. 2594) ABSTRACT OF THE DISCLOSURE An apparatus for diluting a stream of liquid preparatory to analysis which comprises a nozzle directed tangentially toward the inner surface of a funnel-like mixing chamber and a conduit for delivering liquid into a diluent stream just issuing from said nozzle. The apparatus further includes a small capacity overfiowfcontainer positioned to receive the mixed liquid and diluent stream, and a second conduit to remove a sample to be tested from said container. Accurate volumetric flow-rate pumps are employed to deliver the liquid and diluent stream to the chamber and to remove the sample from the container.

This invention relates to the analysis of a flowing stream of liquid. This stream may comprise a continuous monitoring stream, or a plurality of sequentially transmitted samples.

The stream is customarily treated for analysis, as by dialysis, heating, solvent extraction and the addition of one or more reagents; and a quantitative measurement for a constituent of interest is obtained by photometric methods, as by colorimetry or flame photometry. US. Patent No. 2,797,149, issued to Leonard T. Skeggs on June 25, 1957 is illustrative of methods wherein the sample stream is dialyzed, a reagent is added to the dialyzate to produce a color reaction, and the reacted stream is :passed through a colorimeter, the light trans mittance of the stream at a particular wavelength being responsive to the concentration of a constituent of interest.

Certain applications of continuous analysis require the sample liquid to be diluted with a relatively large volume of diluent before being further treated for analysis; as for example, when high dilutions, are required for colorimetric techniques, or when highly corrosive liquids are being analyzed. If a plurality of individual samples are being analyzed, then customarily, these dilutions are performed manually. If a continuous monitoring stream is to be analyzed, then a manual technique is not feasible.

Dilutions can be performed in the presently known continuous analysis systems. If individual samples are to be analyzed, they may be supplied to the system by a sampler such as is shown in US. Patent No. 3,038,340 issued to Jack Isreeli on June 12, 1962. There an off-take tube coupled to a pump tube operated by a peristaltic type pump, such as is shown in US. Patent No. 2,935,028 issued to Andres Ferrari, Jr. et al. on May 3, 1960, aspirates the sample from a container into the system. If a monitoring stream is to be analyzed, then its flow into the system will be similarly controlled by a peristaltic :pump. With direct dilution, a dilution of 1 to 50 or 100 is the maximum which is practical.

A system wherein much higher dilutions can be obtained has been disclosed in US. patent application Ser. No. 497,679 filed by William J. Smythe et al. on Oct. 19, 1965, and assigned to a common assignee. In that system a jet of diluent liquid aspirates the sample liquid into its stream. That system is admirably suited for purposes, however, it may not be as accurate with highly volatile sample liquids as with relatively non-volatile liquids.

Accordingly, an object of this invention is the provision of a system wherein dilutions of the order of magnitude of 1 to 1,000 may be conveniently obtained with sample liquids irrespective of their volatility.

A feature of this invention is the provision of a high dilution system comprising: delivering a stream of diluent liquid from a nozzle; introducing a stream of sample liquid into the diluent stream; directing the sample containing diluent stream tangentially against an inner annular surface; providing a swirling, mixing effect; pooling and turbulently mixing the swirled liquids in an overflow container; and continuously removing an aliquot of the diluted sample from the overflow container.

These and other objects, features and advantages of this invention will be more fully understood from the following description considered in conjunction with the accompanying illustrative drawing, in which:

FIG. 1 is a view in elevation, partially'schematic, of an embodiment of this invention; and

FIG. 2 is a plan view, in section, taken along plane 2-2 of FIG. 1.

The dilution system comprises a constant delivery, variable flow pump 10 having an inlet coupled to a source, not shown, of diluent liquid, and having an outlet coupled by a conduit 12 to a nozzle 14. The nozzle is disposed within a funnel 16 and is oriented to direct its stream tangentially to the inner side wall of the funnel. A low volume, constant delivery pump 18, such as the peristaltic proportioning pump illustrated in US. 2,935,028 supra, includes a pump tube 19 which has an inlet coupled to a source, not shown, of the sample liquid, and an outlet coupled by a conduit 20 to a nozzle 22. This nozzle is disposed within the funnel 16 and is oriented to introduce its sample stream directly into the diluent stream as it leaves the nozzle 14. The diluent stream, containing the sample, swirls onto and downwardly around the inner wall of the funnel, the swirling effect providing excellent mixing of the stream. The outlet 24 of the funnel is disposed within a container 26, which is disposed within a container 28. The liquids pass from the funel outlet 24 into the inner container 26, overflow from the container 26 into the outer container 28, and pass through an outlet 30 to waste. The end of the funnel outlet 24 is advantageously disposed at least half way down the height of the container 26, and preferably closer to the bottom of the container to maximize the turbulence of liquid in the container, thereby providing further mixing of the stream. An off-take tube 32 has its inlet 34 disposed within the inner container 26, and its outlet coupled by a conduit 36 to a pump tube 38 of the pump 18. The pump tube 38 delivers a predetermined volumetric rate of flow of the diluted sample from the container 26 to the analytic apparatus, not shown.

The pump 10 may deliver a fiow of diluent of 1,000 ml./ min. While the pump tube 19 may deliver a flow of sample of 1 mL/min. to provide a dilution of 1,000 to 1. embodiments of this invention operating at 100:1 and 500:1 have shown excellent mixing characteristics with noise of less than /2% transmittance at transmittance in a 50 mm. flow cell for periods greater than one hour.

While there has been shown and described a preferred embodiment of the invention, it will be understood that the invention may be embodied otherwise than as herein specifically illustrated or described, and that change in the form and arrangement of the parts and in the specific manner of practicing the invention may be made without departing from the underlying principles of this invention within the scope of the appended claims.

What is claimed is:

1. Liquid sample supply apparatus comprising: an inner annular surface; a nozzle for directing a stream tangentially at said surface; means for delivering a diluent liquid through said nozzle as a stream at a predetermined volumetric raate of flow; means for delivering a sample liquid into said stream as it leaves said nozzle at a predetermined volumetric rate of flow; container means in liquid flow communication with said inner annular surface, and having an outlet; whereby said sample containing diluent stream swirls around within said inner annular surface, intermixing said sample and said diluent, discharges from said surface into said container means and discharges therefrom through said outlet; and means in fluid flow communication with said container means for withdrawing liquid therefrom as a flowing stream at a predetermined volumetric rate of flow for transmission elsewhere.

2. Apparatus according to claim 1 wherein said inner annular surface is comprised by a funnel having an outlet disposed below the top and above the bottom of said container means.

3. Apparatus according to claim 2 wherein said outlet of said container means is disposed above said outlet of said funnel.

4. Apparatus according to claim 3 wherein said withdrawing means comprises an oif-take tube having its outlet coupled to a source of suction and its inlet disposed within said container means.

5. Apparatus according to claim 1 wherein the ratio of volumetric rates of flow of diluent to sample is provided in excess of 100: 1.

References Cited UNITED STATES PATENTS 2,724,580 11/ 1955 Reuallier 259-4 3,074,784 1/ 1963 Ferrari 23-25 3 3,080,218 3/ 1963 Gustafson 23-25 3 3,193,355 7/1965 Fuhrmann 23230 FOREIGN PATENTS 535,259 1/1957 Canada.

WALTER A. SCHEEL, Primary Examiner.

ROBERT 1. SMITH, Assistant Examiner. 

